Volume Shadow Copy Service blocks disk defrag

Q. When I try to do a disk defragment on my C drive it goes as far as 3% done and gives me a "Paused for Volume Shadow Copy" message. Any thoughts?

A. The Volume Shadow Copy Service — VSS for short — the Windows service that allows your computer to perform data backups from your hard drive even while you are using the computer.

VSS is often enabled when you install backup software like Carbonite, Acronis and Norton Ghost on your computer, but is also used by Windows for the built in System Restore.

When performing disk maintenance like a disk defrag, you might want to turn off VSS temporarily.

To do this open up the Services control panel by clicking on Start then Run and typing services.msc and hitting enter. If you are using Vista or Windows 7 just hit Start and type services.msc on the search box and hit enter.

In the window that pops up, scroll down to Volume Shadow Copy and double click it and then set startup type to disabled and where is says Service status click on the Stop button. This will both stop the VSS service and stop it from running automatically. Be sure and make a note of the Startup type original setting as you will be changing it back when you are done.

When you complete you defrag you can then open up the Services control panel again and change Startup type back to the original setting and restart the service by clicking on Start under Service status.